The purpose of the Blood Drawing for Component Preparation is to obtain cells, proteins, DNA and lipids from healthy volunteers and dyslipidemic subjects for use in research. Some of the blood is used in the preparation of lipoprotein fractions (i.e. VLDL, LDL and HDL) for use in cell culture studies of cholesterol metabolism. Our laboratory is trying to identify common mutations in the population that contribute to the variation in lipoprotein levels and atherosclerosis susceptibility between people. In this work, we use the lipoprotein transport genes as candidate genes, although we are also trying to identify other genes that might be important such as those which regulate cholesterol absorption or the blood vessel wall response to hypercholesterolemia. Recent work suggests that mutations which affect the level of expression of the apo CIII gene may cause hypertriglyceridemia and our lab is trying to determine how this occurs. Another area of research relates to studies of apolipoprotein gene expression and how this might influence plasma lipoprotein levels. Another area of interest is the regulation and role of apolipoprotein E (apoE) with a focus on issues relevant to human disease. There are three common allelic variants of apo E in humans, leading to three protein isoforms E2, E3, and E4. Recently a strong association of the E4 allele with Alzheimer's disease has been found. Our group is attempting to find a mechanism for this association as well as with atherosclerosis and decreased longevity.